In some communication scenarios, a communication device such as a two-way radio may be wirelessly coupled via a short range wireless link (such as a Bluetooth link) to a peripheral device that has buttons, indicators, and other features such as a push-to-talk button (PTT) for activating a PTT feature on the radio. In such a case, the button states, indicator states, and the PTT state for the radio are sent wirelessly between the two devices using the short range wireless link. Some customers, such as public safety customers, desire a very small latency period between a user pressing the PTT button on the peripheral device and a corresponding PTT command (e.g., PTT PRESS or PTT RELEASE) reaching the radio core, which cannot be realized in known systems. Low latency can be extremely important for a PTT PRESS, for example, because a latency that is too long can result in truncated voice if the user begins to speak but the radio has not been activated via the PTT PRESS to enable transmission of all of the user's initial voice messages; this is could mean the difference between a user saying “don't shoot”, and having “shoot” come out in the transmitted message.
In known systems, much of the latency is caused at the peripheral device. For instance, there may be “blockage” at the peripheral that prevents the PTT state from being sent immediately, such as when the peripheral has already begun sending a message or has a buffered data stream when the PTT button is pressed. In this case, the PTT indication must wait to be sent until the other message has been sent and/or the buffer cleared; or the peripheral would have to otherwise abandon the currently transmitting and/or buffered data in some crude way. Additional overhead at the higher layers of the peripheral can further increase the latency of the PTT state transmission. For example, a Bluetooth chipset with a Virtual Machine (VM) in a headset or a small PTT device has so much overhead at the higher layers that the latency from the time the PTT button is pressed on the peripheral to the time the PTT message is received at the Bluetooth controller of the radio can be on the order of 100-400 ms; Bluetooth chipsets with no VM can still incur a latency around 70-120 ms. A wireless adapter at the radio side also adds to the latency of the PTT state reaching the radio core due to the decoding process within the higher layers of the radio side wireless adapter software stack, especially if the radio side wireless adapter manages multiple Bluetooth profiles for multiple peripherals coupled to the radio, which increases the processor load needed to manage the various corresponding data messages and route them to the proper destinations.
Thus, there exists a need for a mechanism for reducing the latency in communicating high priority data, such as a PTT state, from a peripheral device to a wirelessly coupled communication device.